The present invention generally relates to shielded containers for the handling of radioactive materials and, more particularly, to a radiation-resistant, or radiation-dense, shield allowing the improved handling and discharge of a syringe containing a radioactive material.
In the nuclear medical industry, radioactive drugs are used for various applications, including internal imaging of various physiological functions for diagnostic and therapeutic purposes. Over the years, the medical industry has developed many different radioactive drugs that are designed to facilitate imaging and treatment of physiological functions.
Generally, radioactive drugs are in a liquid form that is suitable for injection into a patient. Because of the radioactive characteristics of these drugs, they must be handled according to regulations promulgated by various departments of the United States government, including the Department of Transportation (DOT), the Nuclear Regulatory Commission (NRC), and the Occupational Health and Safety Administration (OSHA). Accordingly, hospitals that administer radioactive drugs to patients must invest in the equipment and the training necessary to meet the requirements of such regulations.
Typically, a patient requires only a small dose of a specific radioactive drug. Therefore, depending on the number of patients, it is generally not economical for one hospital to maintain the staff and equipment to produce the radioactive drugs required by its patients. Furthermore, the radioactive agents in the drugs have various half lives and thus lose their effectiveness to varying degrees as they age. Thus, if a hospital does not have the required demand, some of its inventory of radioactive agents may decay and become unusable. To avoid the expense of such in-house production of radioactive drugs, many health care providers now purchase each prescribed dose of a radioactive drug from an outside radiopharmacy.
The radiopharmacies which deliver radioactive drugs to hospitals utilize the principles of mass production to reduce their per-unit costs. The radiopharmacies receive prescription orders and deliver the corresponding radioactive drugs to nearby hospitals. The radiopharmacies fill each prescription by packaging each dose of radioactive drug in a syringe intended for a specific patient. The syringes containing the radioactive drugs must be carefully handled and delivered inside containers offering some degree of radiation shielding.
One type of delivery container currently used for the delivery of syringes containing radioactive drugs is known as a radiopharmaceutical pig. One type of radiopharmaceutical pig has an interior chamber lined with a radiation-shielding material, typically elemental lead, to safely enclose one syringe. This radiopharmaceutical pig is described in U.S. Pat. No. 5,519,931, issued to Syncor International Corporation and incorporated herein by reference.
Once the radiopharmaceutical pig containing the filled syringe arrives at the hospital, the syringe is removed for use. Because the syringe is radioactive, it is placed into a radiation-resistant shield to protect hospital workers from radiation exposure while they manipulate the syringe to inject the contents of the syringe into the patient. After the dose is injected into the patient, the syringe is referred to as "spent" although it generally contains a small amount of residual radioactive drug. In addition to the radioactive contamination, the hypodermic needle of the spent syringe is biologically contaminated from contact with the patient. If the radiopharmacy offers disposal services, the spent syringe may be placed back into the radiopharmaceutical pig for a return trip to the radiopharmacy.
One conventional syringe injection shield has a hollow cylindrical body with an upper opening for accepting the syringe and a lower opening through which the needle of the syringe projects when the syringe is inserted inside the shield. The shield is made of radiation resistant metal, such as tungsten, and also includes a lead glass window so that a hospital worker can view the amount of the drug within the syringe. A spring-biased lever is mounted in a slot in the side of the body. The lever extends inside the body to frictionally engage the syringe.
The body of the shield has a length commensurate with the length of the body of the syringe to allow the hypodermic needle and the plunger of the syringe to project from each end of the shield. Because the shield must allow the health care worker to position and discharge the syringe, the shield cannot interfere with the insertion of the needle into the patient and the downward movement of the plunger to inject the radioactive drug into the patient. As is commonly known, the upper portion of a syringe body has a base with flanges projecting radially outwardly therefrom. Because the flanged base of the syringe is somewhat larger than the upper opening of the shield, the syringe will not slip out of the shield as downward force is applied to the syringe's plunger. Because of the expense of radiation-resistant syringe shields, hospitals typically sterilize them for reuse.
The aforementioned syringe shield is generally effective. However, one drawback associated with this injection shield design is that with each use it is exposed to the biologically contaminated needle of the syringe and thus must undergo expensive advanced sterilization procedures before it can be reused. In particular, after the syringe is discharged, the syringe is removed from the shield and placed back in the radiopharmaceutical pig for disposal. Because the flanged base of the syringe is larger than the upper opening of the shield, the syringe can only be removed by withdrawing it in an upward direction, thereby causing the contaminated needle to pass back through the inside the shield as the syringe and shield are separated. Therefore, as the spent syringe is removed from the shield, the contaminated needle can touch the inside surface of the shield. Accordingly, expensive advanced sterilization procedures must be employed upon the shield before it can be reused. Such a process is expensive and, therefore, undesirable.
Accordingly, there exists a need for an injection shield and method for discharging a syringe containing radioactive material that avoids the need for the aforementioned expensive sterilization procedures. The present invention satisfies this need and provides further related advantages.